Along with the continuous growth of the Internet, various network services appear, and advanced multimedia systems emerge in endlessly. Since real-time services are relatively sensitive to network characteristics such as transmission latency, delay jitter etc., when there are FTP services of high burstiness, or HTTP services with image files on the network, the real-time services may be greatly affected. Besides, since multimedia services may occupy much bandwidth, key services, which need to be guaranteed in the existing network, can not be reliably transmitted. Therefore, in order to guarantee reliable transmission of key services, various QoS technologies arise. The Internet Engineering Task Force (IETF) has proposed a good many service models and mechanisms to satisfy QoS requirement. At present, a scheme, which adopts an Integrated Service (INT-SERV) model on the access or edge area of a network, and adopts a Differentiated Service (DIFF-SERV) model on the core area of the network, is comparatively approved in the art.
In the Diff-serv model, a measure of setting priority levels is provided to guarantee the QoS. Although this model has a feature of high line efficiency, the real effectiveness is unpredictable. Therefore, an independent bearer control layer is introduced into the Diff-serv Model of the backbone network in the art, a special set of Diff-serv QoS signaling mechanisms are provided, and also a resource management layer is specially established for the Diff-serv network, which is used for managing topology resources of the network. This Diff-serv mode of resource management is called a Diff-serv model with an independent bearer control layer. FIG. 1 is a schematic diagram of the model. The 101 is a service server, such as a Call Agent (CA), which belongs to the service control layer for implementing functions such as soft switch. The 102 is a bearer network resource manager which belongs to the bearer control layer. Solid circles, such as the 103, are Edge Routers (ER); hollow circles, such as the 104, are Core Routers (CR), and circles filled with skew lines, such as the 105, are Boundary Routers (BR). Here, the ERs, CRs and BRs all belong to the bearer network, so they can be generally called as Connection Node (CN), and the CRs and BRs together can be called as Transmit Router (TR). In FIG. 1, every dot line ellipse in the bearer network represents a management domain, which is managed by a bearer network resource manager, and each domain includes a BR or an ER, and several CRs.
In the model of FIG. 1, the bearer network resource manager is in charge of configuring managing policies and network topologies, allocating resources for service bandwidth applications of users. The users' service bandwidth application requests and results, and path information of the service applications allocated by bearer network resource managers are transferred among the bearer network resource managers of management domains by signaling. When processing a user's service bandwidth application, the bearer control layer may define a route for the user's service, and the bearer network resource manager may inform the ER to forward the service stream according to the defined route.
Here, the route stored in a bearer network resource manager includes: a signaling route and a service route. The signaling route refers to a procedure how a bearer network resource manager looks for a next hop bearer network resource manager, and the service route, including an intra-domain route and an inter-domain route, refers to a procedure how a bearer network resource manager looks for an appropriate bearer LSP according to information of the service stream.
Usually, users' service streams are forwarded on the bearer network according to paths designated by the bearer control layer. Presently, a Multi-protocol Label Switching (MPLS) technology is employed in the art to establish a LSP via resource reservation according to the path of service stream designated by the bearer control layer; or a Resource Reservation Protocol-Traffic Engineering (RSVP-TE) protocol, or an explicit routing mechanism such as Constraint Routing-Label Distribution Protocol (CR-LDP) is employed to establish an end-to-end LSP.
In a bearer network, reliability guarantee is very important. At present, there is a good deal of methods to guarantee reliability in a bearer network, and the simplest one is cold backup, which means using one network entity as a complete backup of another network entity. For example, entity B is taken as a cold backup for entity A. When entity A fails, the backup entity B will totally substitute for entity A. Of course, both bearer connections and service connections of former entity A should be rebuilt in this case.
The cold backup method is easy to implement at the initial stage of network construction, when switching and smoothing are not needed in real time by nodes. However, this method is only suitable for a small-size network, because the small-size network has following characteristics: small traffic volume, relatively low real-time requirement, allowable to interrupt and rebuild connections, and unnecessary for LSPs to perform hot switching.
The inventor found: in a network with an independent bearer control layer, when LSPs are used as paths for bearing service streams, it lacks effective protection for the LSPs at the present technical scheme. In this case, when a failure appears on an LSP, service streams born on the LSP will be interrupted, which may give an undesirable impact on users' service experience.